Retrofitting with HFCs
So, more than ever, the industry has been looking for alternatives to R-22 to keep the huge existing base of R-22 equipment up and running. More reclamation has been one option. But at the same time, attention is being paid to a large number of HFC refrigerants that can be retrofitted into R-22 equipment.
Early in 2012, the EPA “proposed to significantly reduce allowances to produce and/or import virgin R-22 ranging from 11-47 percent per year over the period 2012-2014 for servicing existing R-22 equipment,” according to a statement from DuPont. The company said, “In the absence of a final rule for 2012, the EPA issued an Assurance of No Action letter in January which gave the EPA authority to implement the maximum reductions for 2012. Either the final rule or another Assurance of No Action letter will need to be issued for 2013.”
So the math is simple: Around 100 million pounds of virgin R-22 was produced in 2011. Expect about 55 million pounds in 2012 and significant reductions through 2014.
HCFCs are being phased out because of issues with ozone depletion potential (ODP). It is happening internationally in most countries at a much faster pace than in the United States.
The fact that the phaseout of R-22 is taking place globally caused Bitzer to state in a recent report, “Due to this situation, enormous consequences result for the whole refrigeration and air conditioning trade. Therefore close cooperation exists with scientific institutions, the refrigeration and oil industries, component manufacturers as well as a number of innovative refrigeration and air conditioning companies” to address the changes taking place. One part of that is HFCs as retrofit refrigerants.
HFCs do not have the ODP issue and are at present not subject to any official phasedown directives. Thus, they have caught the eye of manufacturers, contractors, and end users as a way to keep existing R-22 systems running without R-22.
A Cautionary Tale
But there are challenges in doing so. According to Will Gresham, national sales manager for Dynatemp International, “When retrofitting an R-22 system with any HFC refrigerant, the technician must be acutely aware of the system’s operational characteristics before the retrofit. R-22 systems were designed and developed to perform ideally with R-22, and measures must be taken to ensure the system achieves maximum efficiency with a refrigerant that is not R-22.
“Every R-22 retrofit is unique, with some systems needing little to no change to achieve the desired operational characteristics, while some may need additional modifications, such as changing the orifice or TXV size to achieve the same efficiency.
“Any time a retrofit is called for, it is only prudent that a technician take the unique characteristics and performance of each system into account.”
One important aspect regarding HFC retrofit refrigerants is that “no one refrigerant can replace R-22 best in its (R-22’s) entire application range, so we have alternatives depending on the intended application,” said Gus Rolotti, technical marketing director of Arkema’s North American fluorochemicals business.
In general, noted Rajan Rajendran, vice president of engineering services and sustainability for Emerson Climate Technologies, “One has to be careful retrofitting HFCs into HCFC systems — components, oils, etc., all need to be looked at carefully.”
System performance is another issue contractors need to factor into their choices.
Jeff Staub, application engineering manager of Danfoss, said, “Based on the choice of refrigerant, there can be a loss in system capacity which could directly affect the system resulting in a lack of cooling for products or buildings. There could be a significant loss in efficiency which could negatively affect utility bills for an end user.
“However, if a proper system evaluation is performed and considerations are taken to ensure the continued reliability of the system, then retrofitting should be seen as a viable alternative to the use of HCFC in refrigeration applications.”
According to Ron Vogl, technical marketing manager for Honeywell Refrigerants, “Generally speaking, one can see system improvements after a retrofit as a result of recommissioning the equipment. These performance improvements are the result of properly setting up the controls and system operating valves such as thermal expansion controls, which may have wandered from setpoint due to lack of maintenance, etc.
“For proper performance, it is a must to evaluate the head pressure management controls (if present) during the retrofit. Setting up the evaporator operating pressure and the system’s condensing pressures for the selected replacements specific pressure temperature relationship is imperative. Leaving R-22 setpoints will lead to subpar performance and/or increased energy consumption.
“The technician must be aware that all new HFC substitutes for R-22 are blends and possess glide. The technician must get comfortable with terms such as bubble and dew and know where to apply these values.”
Publication date: 12/3/2012